The present invention generally relates to alarm devices and more particularly to an alarm condition transmitter device which includes an energy conversion device for converting an available predetermined form of energy into electrical energy for charging an energy storing element, within the alarm device, for continuously maintaining the latter in a ready or standby mode.
Various alarm systems are already known. With most conventional alarms, expensive wiring is required for interconnecting the switch transducers placed at the openings or apertures of a chamber to be protected and the control device, as well as with the alarm indicating device. The interconnecting wiring is inconvenient and time consuming to install and substantially raises the cost of installation of the alarm system. Additionally, the interconnecting wiring is frequently left exposed, this sometimes being unacceptable for aesthetic reasons.
To overcome the interconnecting wiring problem, it has been proposed that transmitter devices be utilized at the openings of the protected chamber or enclosure, which transmitter devices transmit a predetermined signal upon the occurrence of an alarm condition. The transmitted signal is received by a suitable receiver situated within or nearby the chamber being protected. Typically, such transmitters have utilized oscillator circuits. When an alarm condition occurs, the oscillator circuit is energized and the latter transmits a selected frequency or frequencies or tones which can be distinguished by the receiver control device. A disadvantage of the hitherto proposed transmitter devices has been their utilization of batteries for the energization of the output circuits. As is evident, the requirement for battery use is undesirable because batteries must periodically be replaced. Further, the battery does not always display the same high or initial voltage as when the battery is fresh or fully charged. With passage of time, it is difficult to ascertain, without expensive and time consuming procedures, the exact voltage or energy which the battery can provide in the event of an emergency or alarm condition. Consequently, in addition to the expensive maintenance requirement with batteries, the same are not always reliable or predictable with passage of time and malfunction of the alarm system may occur if the transmitter devices are not continuously supervised and checked.